Process for the production of nitrites



lli atented hept. R5, 192%..

mined! U 'lEYUGlENIE 'l. JDRAKE, F OMAHA, NEBRASKA, ASSIGHOE TO THE GU'DAHY PACKING GOMJPANY, OF CHICAGO, ILLINOIS, A. CDRPORATION CF MAINE.

PROCESS FOR THE PRODUCTION OF NITRTTJES.

No Drawing.

The invention relates to the production of nitrites, and specifically to the bacteriological decomposition oi nitrates, the object of the invention being the more rapid, economical and etlicient production of said nitrites.

T have found that nitrites may be produced from nitrates by operating in the following manner.

A Iirst or preliminary culture is prepared of an aqueous solution, for example, oi 2 to 8% sodium nitrate, to of sugar. to 1'? 70 common salt. This solution should contain a protein material in some form ineluding amino nitrogen from 5/109 to 2%; it may be added in the form of peptone or by using a sterilized second pickle containing meat juices. The hydrogen ion concen, tration of this medium is adjusted to between 5 and 10. This medium is rendered sterile 20 by heating at a suitably high temperature for about twenty minutes.

This preliminary culture is then inoculated with pure cultures of one or more of a group oil? bacilli or spirilli which, among other characteristics, have that of convertingnitrates into initrites. These organisms comprise bacilli tor the greater part, but also some spirilli they have not hitherto been isolated or classified, but may be identified by the :lollowing characteristics:

They are non-putreitactive.

They are non-pathogenic.

They are nitrate-reducing.

They are non-proteolytic.

They are motil and non-motil.

They are salt-tolerant.

They are either bacilli or spirilli.

These selected organisms are prepared in pure culture according to the usual practice in bacteriological laboratories from various and well known sources. The pure cultures of the above mentioned organisms are on]- tivated and kept growing upon the customary media used in the laboratory and under the usual conditions of propagation.

As stated, the preliminary culture above described is inoculated with this selected organism, and in order that the conversion from nitrates into nitrites shall take place uninterruptedly and satisfactorily this and succeeding cultures must be contained in a pure culture. They are then allowed to propagate in suitable containers, for example, those the material of which does not retard, injure or destroy the growth. For propagating these Application filed February 8, 1926. Serial No 86,963.

pure cultures the containers are maintained at temperatures between and 110 F, altho success has been attained with a temperature as low oilll. During growth the nitrate is converted into nitrite and the sugar is fermented to carbon dioxide and acids, which is a change induced by the pure cultures of the bacteria added. During this period of growth, the hydrogen ion content, having been modified by the 'lormation of the above mentioned acids, which modification or decrease retards the growth ot' the specific or- ,eganismt-i involved, must be constantly adj usted to the limits mentioned above, and this may be done in any suitable and well known manner. It is, 01 course, understood that the pure culture may be added in any amount.

A second culture is then prepared in exactly the same manner as that described for the preliminary culture, the quantity thereol. being approximately twenty times that of the preliminary culture. About 1% of the preliminary culture is added to this second culture, which allowed to grow under the Fame conditions of ten'ipcratin'e and tor the same period of time as the preliminary culture.

A third culture is then prepared in the same manner as the preliminary and second. culture, this third culture being approxin'lately twenty times the amount of the second culture; to this third culture is added about 1% 01 the second culture, which is allowed to grow from 24; to 18 hours, the hydrogen ion concentration being adjusted and maintained as in the previous cultures; it is then ready for use in the final or working culture;

Tn these three cultures it is highly advantageous that a constant supply of oxygen be supplied, which may be done for example by aeration.

For the final. or working culture, viz, that to be manufactured tor-use or sale, a solution is prepared in quantities suitable for the amount of nitrite to be produced, to which 1 to 3% of the third culture is added. This solution is of the same composition as the solutions used in the preliminary culture, and also in the second and third cultures. The culture which, as stated, is taken from the third culture, is allowed to grow in the solution for approximately six days at a temperature of from 70 to 110 F, oxygen being constantly added, preferably by aera ltll) llllll tion, and the hydrogen ion Value being maintained as in preceding cultures. The culture is allowed to grow until practically all the nitrate has been converted into nitrite through the action of the previously mentioned selected organisms. This growth being completed the working culture is heated to sterilization temperature and the action of the bacteria completely arrested. This solution of nitrite is then ready for use per se or may be converted into solid form, a salt, for example, by well known evaporating and refining methods. By controlling the amount of sugar and salt used in the working'culture is is possible to control the residual quantities of these ingredients in the finished product.

It is to be understood that the invention is not lin'iited to the exact constituents, proportions and time intervals set forth. For example, othernitrates may be used instead I of sodium nitrate, and the sugar used may be o'fany type. It is possible to vary the time otgrowth in the preliminary culture and the second and third cultures, increase the number of cultures or change the ratio of the factors to control or accelerate the rate of growth, but the time intervals and quantity ratios given have been found generally preferable. In the preliminary cultures the rate of growth of the bacteria and the number produced is determined by analysis and number of bacteria present showing the rate of denitrific'ation.

I claim 1. A bacteriological process for the conversion of nitrates into nitrites which comprises inoculatinga series of cultures formed of an aqueous solution of sodium nitrate, sugar, common salt and amino nitrogen, with selected groups of non-putretactiye, non-pathogenic',, nitrate-reducing, non-proteolytic, mo til and non-motil, salt-tolerant bacilli having the property of converting nitrates into nitrites.

2. A bacteriological process forthe conversion of nitrates into nitrites which comprises inoculating a series of cultures formed of an aqueous solution of sodium nitrate, sugar, common salt and amino nitrogen, with selected groups of non-putretactive, non-pathogenie, nitrate-reducing, nonproteolytic, motil and non-motil, salt-tolerant spirilli having the property of converting nitrates into nitrites.

3. A process For the production of uitrilcs which comprises the selection of certain types oi. bacteria having properties described in claim 1, inoculating with said bacteria a prelin'iinary culture prepared as sct tori h in claim 1, allowing this preliminary culturc to grow tor a specified period of time under specific conditions of temperature, utilizii'ig 1% ol this preliminary culture For the fOllilZlilUll of a second culture prepared in the same manner as the preliminary culture, but in amount times as grca allowing this second cul ture to grow under the same conditions as the preliminary culture; utilizing about 1% of this second culti'u'c to produce a third culture under the sauna conditions as the second culture, oxygen, being preferably added during the process of producing all three culturcs; utilizing to 23% of: this third culture for producing; a final or working culture, in which the action of the organisms selected is allowed to ciiint-iuuc until the nit-rates are couycrted into nitritcs.

A process tor the production of nitritcs which comprises the selection of certain types of bacteria ha ing properties described in claim 1, noculating with said bacteria a prelin'iinary culture prepared as set forth in claim 1, allowing this preliminary culture to grow for a specified period of time under spocitic conditions of temperature, utilizing 1% of this preliminary culture for the tormution of a second culture prepared in the same manner as the preliu'iinary culture, but in amount 20 times as great, allowing this sec- 7 end culture to grow under the same conditions as the preliminary culture; utilizing about 1% of this second culture to produce a third culture undert-he same co'lulitious as the second culturc .'ox v;rcn being preferably added during the process of producing all three cultures; utilizing l to 3% of this third culture for producing a final or working culture, in which the action of the organisms sclected is allowed to continue until the nitrates are converted into nitrites, and reducing the solution containing the uitritcs to solid form.

In testimony whereof 1 ha re hcrcuuio sci. my hand.

E U GEN E T. DRA K I 

